Conventionally, when a relatively flat (including slightly pitched) roof is used as a functional balcony or terrace, material is installed over (on top of) the waterproofing membrane/roofing both for aesthetic and practical reasons. Examples of this include a wood deck with non-penetrating framing (sleepers), or a cast paver (such as a split brick paver). Another surface material (somewhat less common) can be, for example, a poured concrete surface with expansion joints.
Installation of such surface material extends the life of the waterproofing membrane or roofing by protecting it from foot traffic as well as from the elements. Such surface material can also weigh down the waterproofing membrane, thus helping to ensure that over time it is less likely to pull away from substrate, especially around the edges.
It is noted that water is likely to penetrate an installed surface material. If a roof has a pitch—for example, the International Residential Code requires a minimum pitch of ¼″ per foot—directed towards one or more of the edges, rain water will end up at these edges.
Sometimes, in such cases, a roofing membrane is adhered down the outside vertical surface of the perimeter fascia. Additionally, the roofing membrane may overlap with, and deposit water into, a gutter. This technique generally exposes the full outside edge of the installed surface material as well as the vertical leg of the roofing membrane that overlaps the fascia or gutter. In such instances, the roofing membrane may rely solely on an adhesive to remain attached to the vertical outside face of the fascia or inside vertical face of gutter. An alternative that may be desirable both for aesthetic and structural purposes would include the utilization of an installed edging flashing.
Such an installed edging flashing can act to retain the installed surface material which can, by virtue of its weight, apply pressure onto the perimeter of the roofing membrane thereby helping it to stay adhered. Such edging flashing can also hide the lower outside perimeter edge of the surface material, any substructure for the surface material or drainage material, and the roofing membrane. Some may consider this utilization of an edging flashing to be more aesthetically pleasing.
It is important to allow for drainage when installing an edging flashing that rises above the upper surface of the membrane in order to border/retain/edge an installed surface material. If the roof is pitched towards one or more of the roof edges, water must be directed out and away from the roof, into a water collection device such as a gutter.
Conventionally, there are many devices used to edge the perimeter of a roof and retain a surface material. These devices, however, do not allow for water drainage if water were to get under the installed surface material. Accordingly, such devices can be of service if drainage occurs somewhere within the roof area and the roof is pitched towards that drain. However, when water is directed by the pitch of the roof towards the outer edges, ponding will occur if the edging system does not allow for that water to pass. Also, such conventional devices generally consist of two or more parts, making them both more difficult to install and more costly to manufacture—especially devices using extruded components.
Some devices utilize holes in the vertical edging in order to manage water. If a surface material butts into such a vertical edge, the holes may be partially or completely blocked so that the water may be slow to release and ponding can still occur. Additionally, the aesthetic of having visible holes along the edge flashing may not be desirable.
Edging with holes in the outer vertical surface may also not account for a variance of pressure applied by the surface material. Often a roof surface is not perfectly square. In such instances, the installed surface material may have to be cut at a slight angle or the surface material may push at different pressures along the edging. In this case it would be useful to have some flexing range in the edging product that helps take into account this variation in layout. If a conventional vertical edging surface is pressed out by the abutment of an installed surface material, a gap may start to open up between the edging and the surface material. Such a gap could collect debris over time and become less aesthetically pleasing. Also, such edging may become noticeably pitched if pressed out by the abutting surface material.
One example of a one-piece flashing that is used as edging on a flat roof is shown in U.S. Pat. No. 8,739,470. The single piece of flashing folds over the side of a roof, protrudes downward, and then folds over itself, having an outer vertical edge that rises up over the level of an installed surface material, and folds over, at a ninety degree angle, the installed surface material, which is then clamped down by the top horizontal surface of the flashing, as shown in FIGS. 1-3 thereof. One challenge of such flashing is that there are many different thicknesses of surface material. The flashing would need to come in many sizes to accommodate the varying thicknesses of available material, or have the ninety degree fold where the outer vertical face becomes the top horizontal face be bent (or unbent) to accommodate different sizes. Also, if the desired surface material to be installed is not of consistent thickness, gaps under the irregular upper horizontal surface of the flashing could collect debris.
The top horizontal surface of the flashing (item 16 in FIGS. 1-3) that covers the surface material may also need to be adjusted or cut if posts for a guard railing are installed close to the roof edge. It is here noted that the International Building Code requires decks, terraces and balconies to have a guard rail if they are of a height greater than thirty-two inches (32″) off of the ground.
What is thus needed in the art are flashing treatments that overcome the above-described problems of the prior art.